News from the College of Food, Agricultural, and Environmental Sciences

Increasing the reproductive efficiency of dairy cattle -- getting the highest possible number of cows pregnant in the same period of time -- has always been a challenge for this industry. Ohio State University specialists are working to reverse this trend through the development of new reproduction techniques and training that emphasizes proper management.

Currently, the national pregnancy rate for dairy cows is only 16 percent, while the benchmark rate set by industry experts is 10 points higher, said Gustavo Schuenemann, Ohio State University Extension's state dairy veterinarian. Ohio's rate is about the national average, he pointed out, so there's room for improvement.

Lower pregnancy rates are an issue for the dairy industry because they translate into reduced herd growth and potential loss of profits, said Mike Day, an animal scientist with the university's Ohio Agricultural Research and Development Center (OARDC). "Dairy cows work hard every day," he said. "That makes it more difficult for farmers to increase reproduction rates."

One way dairy farms can boost their reproduction efforts is the use of artificial insemination (AI) and estrus (heat) synchronization techniques. Working with industry partners, Day and his research team have pioneered a new fixed-time AI protocol -- known as "5-day CO-Synch + CIDR" -- that better synchronizes a cow's estrus cycle so that AI can be administered when cows are more fertile.
Mike Day (middle) works closely with industry partners, including Select Sires of Plain City, Ohio. (Photo by Ken Chamberlain)

A recommended practice within the beef cattle industry nationwide, this protocol has been successfully tested on beef cows, resulting in 60 to 70 percent of animals getting pregnant within one day -- a 17.5-percent increase compared to industry standards. Day and colleagues calculated that if 5-day CO-Synch + CIDR were implemented with just 10 percent of Ohio's roughly 500,000 beef and dairy cows, the total economic benefit would easily surpass $5 million in savings and increased production.

This protocol is now being studied in dairy heifers and cows by researchers at various locations across the country, Day said. The hope is that this approach will increase fertility in dairy cattle compared to current protocols, giving farmers another tool to inch closer to their reproductive goals.

While technology is an important factor in boosting reproductive efficiency of dairy cattle, it's not the solution by itself, according to OSU Extension's Schuenemann.

"There's no magic bullet," said Schuenemann, who develops and coordinates research-based, practical training workshops for dairy producers, personnel and veterinarians throughout Ohio. "There are many tools out there -- from synchronization protocols to heat detection to measuring cow activity -- but regardless of the tool a farmer may use, proactive management practices at the farm level matter when it comes to reproduction."

One of the things Schuenemann emphasizes in his training programs is proper management during the transition period, which is three to four weeks prior to calving and approximately one month post-calving. This, he said, is "key to reproductive success." Some of the issues that dairy farmers need to address during this crucial period include avoiding overstocking of animals and commingling (mixing together) of mature cows with heifers; making sure cows get balanced food rations; and having a reliable and well-trained group of workers who can properly handle calving and identify and assist cows that experience difficult births as well as sick cows after calving.

Proactive management also involves choosing the right tool or set of tools to maximize reproductive success.

"The choice of reproduction protocol needs to match the particular conditions of each farm, its resources, its objectives and the skill of its workers," Schuenemann explained. "All dairy farmers are unique, even if they are only a mile apart from each other. So it's very important to assess human resources on the farm. Some may adopt techniques that are more time-sensitive and cost more in synchronization hormones, but which have the potential for higher pregnancy rates. Others may do better with heat detection and trying to take advantage of normal estrus.

"You don't want a farmer to fail because he picked a technique that doesn't work for his conditions. Every farm is an integrated system; decisions made on one area of the farm will have an impact on other areas of the farm."